There are two automatic input selection modes that can be set by register: Auto Revertive and Auto Non-Revertive.
- Auto Revertive: In this mode, the DPLL automatically selects the valid
input with the highest configured priority. If a
clock with higher priority becomes valid, the DPLL
automatically switches over to that clock
immediately.
- Auto Non-Revertive: In this mode, the DPLL automatically selects the
highest priority input that is valid. If a higher
priority input because valid, the DPLL does not
switch over until the currently selected input
becomes invalid.